Wireless-interference prevention



March 2 1926.

N J. SLEPYIAN WIRELESS INTERFERENCE PREVENTION Filed August 18 1921 2 /4 I I 4 g 4 4. i d I I l WITNESSES: INVENTOR I I Jog ph 5/ep/an.

' ATTORNEY Patented Mar. 2, 1926.

UNITED STATES PATENT OFFICE.

JOSEPH BLEPIAN, OI SWISSVALE, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE I ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

WmELESS-IN'IERFERENCE PREVENTION.

Application filed August 18, 1921., Serial No. 493,357.

To all whom it may concern:

Be it known that I, JOSEPH SLEPIAN, a citizen of the United States, and a resident of Swissvale, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Wireless- Interference Prevention, of which the following is a specification.

My invention relates to means for preventing .circuits having characteristics from developing abnormal high-frequency currents, and, more particularly, to means for the prevention of wire less interference. I

An object of my invention is to prevent the transmission of high-frequency waves from a flue-gas treater or electrostatic precipitating device. 7

In apparatus for treating flue gases, negatively charged chains are ordinarily hung in a large electrically conductive pipe. To maintain the chains negatively charged, they have been connected to the negative terminal of a rectifier in a high-tension circuit. The negative corona causes some of the charge to be dissipated, and high-frequency oscillations have thus been set up and transmitted, since the treater circuit corresponds to an open antenna circuit. The frequency of the oscillation is that of the apparatus considered as an open antenna. The high-frequency oscillations have been the cause of wireless interference and are, therefore, objectionable.

To prevent such wireless interference, I resort to either of two methods, or I may combine the methods as desired. Since the treater circuit acts as an open antenna, there is a current antinode at the treater and a voltage antinode at the rectifier end of the high-tension direct-current line. resistor is placed in the circuit in proximity to the treater to damp out the high-frequency oscillations. If the resistor produces too great a current-resistance drop for the normal direct-current load, it may be shunted by a reactor, for which I commonly employ a high-frequency. choke coil. This allows the passage of direct current but prevents the passage of high-frequency currents.

Again, in order to prevent the treater circuit from acting as an o en-end antenna, I may connect it to groun through a conhigh-frequency denser positioned in the circuit in proximity to the rectifier.

Other objects of my invention will be apparent from the following description and claims, when considered in connection with the accompanying drawing, wherein Figure l is a diagrammatic view of a treater embodying my invention.

Fig. 2 is a diagrammatic view, in side elevation, of the slip-ring connections on the rotor of the treater.

In circuit with alternating-current mains 1 and 2 is a primary induction coil 3 which serves as the primary of a step-up transformer. The secondary of the transformer is diagrammatically shown by an induction coil 4:. The ratio between primary and secondary voltages is such that the secondary circuit will operate at a potential of approximately fii'ty thousand to one hundred thousand volts.

The two terminals of the secondary coil at are connected, respectively, to contact members or brushes 5 and 6 that make contact, with slip rings 7 and 8, respectively, on a shaft 9 which carries a rotor 11 of a current rectifier. The rotor member 11 rotates between an upper negative stator element 12 which is insulated and a lower positive stator element 13 which is connected to ground. The upper or negative stator 12 is connected to chains 14 which constitute the interior member of the treater. The exterior member of the treater 15, which is customarily a metallic stack, is connected to ground.

In proximity to the treater end of the treater circuit, I have placed, in series with the treater, a resistor 16. The resistor 16 is of such resistance that the high-frequency current will be damped inits passage therethrough. I have shown the resistor as shunted by a high-frequency choke coil 17 which may or may not be used, as desired. It the resistor produces too great a current-resistance drop for the normal direct-current load, it is desirable to use the high-frequency choke coil 17 Shunting the rectifier-treater circuit in proximity to the rectifier end of the same, I-have shown a condenser 18 connected to ground.

In operation, the treater acts ordinarily as an open-end antenna. In this case, the current antinode is located in proximity to the treater end of the circuit and the voltage antinode in proximity to the rectifier end. The resistor 16, because it is located close to the current antinode,

will act most efliciently at this position because the maximum high-frequency current is at that end. The reactor-17 may by-pass the direct current and is used merely to prevent increase of the normal operating losses of the system.

As previously explained, under ordinary conditions the use of the resistor 16 should be sufficient to damp out the hi'glrfrequency oscillations. However, by using the con denser 18, the system is prevented from becoming an open antenna at any time, sincethe condenser shunts the rectifier so that that end of the circuit is always connected to ground through a path of low impedance to high-frequency currents. High-frequency radiation is thereby eliminated.

I have shown a form of apparatus in which two principles are utilized to prevent high-frequency radiations from a treater in operation, and either one or both methods 0 prevention may be used, preferably both.-

Since I have not shown all the possible modifications of my invention which may occur to those skilled in the art, I desire that my invention shall be limited solely by the appended claims and the prior art.

I claim as my invention:

1. A treater circuit comprising a treater, a source of high-potential alternating current, a rectifier in circuit between the source of high-potential alternating current and the treater, and a condenser connecting the circuit to ground adjacent the rectifier and between the treater and the rectifier.

2. A treater circuit comprising an elevated treater, a source of high-potential alternating current therefor, a rectifier connected in series-circuit relation to said source and said treater, a resistor inserted in circuit with the treater at a point of current antinode, and a condenser connecting said circuit to ground at a antinode.

3. A treater circuit comprising an elevated treater, a source of high-potential alternating current, a rectifier connected in series-circuit relation to said source and said treater, a resistor inserted in circuit with said treater at a point of current antinode, a high-frequency choke coil shunting said resistor, and a condenser connecting said circuit to ground at a point of potential antinode.

4. In a treating system for removing sus pended particles from gases, a source of alternating current of high potential, an elevated line, a rectifier connecting said source to said line, said rectifier leaving the line disconnected during a portion of each cycle, a treater connected between said line and the ground, whereby, upon disconnection of said line by said rectifier, the corona in said treater Willcause the line to function as an antenna, and means for minimizing the radiations from said treater said means point ofpotential v comprising damping devices in the circuit. 5. Ina treating system for removing suscondenser across the circuit at the potential anti-node near the rectifier.

In testimony whereof, I have hereunto subscribed my name this 16th day of August, 192i.

JOSEPH SLEIIAN. 

